Study on Grain Refinement and TiN Coating Post-heat Treatment of 316L Austenitic Stainless Steel
| Autor: | Kuan-Hao Huang, 黃冠豪 |
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| Rok vydání: | 2014 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 102 This study has utilized the two processes, ‘repetitive thermomechanical treatment (RTMT) ’ and ‘post-heat treatment of TiN arc-coating’, respectively, to treat 316L austenitic stainless steel, and then analyzed its structure as well as performed hardness tests, wear tests, and corrosion tests for exploring the effects of both the treatments on the mechanical and chemical characteristics of 316L stainless steel. The results showed that 316L stainless steel after RTMT could refine the grain size to nanoscale to enhance its hardness and strength. In particular, 316L stainless steel treated with 750oC-5 min condition showed the best performance on grain refinement. As a result, the steel had not only the highest hardness, ultimate tensile strength (470 HV, 1385MPa), but also the lowest friction coefficient (0.55) and wear rate (1.06 x 10-4g/m). Dislocation density of the RTMP even lower than the specimen of solution treatment. However, small grains with more grain boundaries with poor corrosion resistance resulted in deterioration of corrosion resistance. Therefore, the method of cathodic arc deposition was further used to modify surface characteristics of 316L stainless steel. When post-annealing temperature of TiN coating was held at 500 oC, there was a Ti-N-O film formed on the surface of 316L stainless steel. Such the annealed coating had the most homogeneous composition, highest hardness (22GPa), and lowest friction coefficient in comparison to other un-annealed and annealed coatings. Consequently, 316L stainless steel with the annealed TiN coating revealed an evident improvement on wear resistance and corrosion resistance. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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